ICMP failure

From:

Vincent Fox

Subject:

ICMP failure

Date:

Sun, 26 Feb 2006 21:17:05 -0800 (PST)

I recently installed a copy of monit 4.7 on an FC4 box to monitor a bunch
of Linksys WRT units in the local network.
At the moment, however it seems very noisy and not useful mainly because I
get certain hosts constantly toggling back and forth as pingable or not. I
cannot account for this behaviour, as ping from the command line to same
hosts works consistently at all times.
I notice this when I do simple tcpdump -vvv:
23:54:31.780384 IP (tos 0x0, ttl 255, id 0, offset 0, flags [DF], proto 1,
length: 28) gw-blue > atlantic1209-ap: icmp 8: echo request seq 0
23:54:31.780402 IP (tos 0x0, ttl 255, id 1, offset 0, flags [DF], proto 1,
length: 28) gw-blue > atlantic1209-ap: icmp 8: echo request seq 256
I am no IP guru here but shouldn't the sequence number returning be the
same? Not sure about id number at all.
Any suggestions for additional debugging information?